Hydro jetting a residential sewer line usually takes one to two hours on site, including a camera inspection before and after the jetting. A light grease clog in a short, accessible line can finish in under an hour. Heavy root intrusion, a long run to the city main, or a hard-to-reach cleanout can push it to three hours.
The jetting itself is often the shortest part. Contractors who itemize it put the first camera run at 15 to 30 minutes, the jetting at 45 minutes to an hour, and the flush, second camera run and cleanup at another 15 to 30 minutes. The camera inspection shows whether an older pipe can take full pressure and whether the blockage is grease, scale or roots, which decides the nozzle and the number of passes.
How long the line stays clear depends on the cause. Grease and scale return as fast as your household sends them down the drain. Roots are different. The U.S. EPA lists jetting as a method that cuts roots in small sewer pipes, but cutting leaves open the joint they got in through, so they grow back. Lining the pipe seals those joints so the roots stop coming back.
Jetting also has a real limit. It cannot fix a cracked pipe, an offset joint, or a belly where the line sags and holds water. If the camera shows that kind of damage, jetting buys time, and the lasting fix is sewer pipe lining or a section repair.